1. Field of the Invention
The present invention relates to a vehicle heating apparatus having a combustor for heating a passenger compartment of the vehicle by burning a fuel, and an exhaust gas recirculation system for recycling exhaust gas.
2. Description of Related Art
In a vehicle having a diesel engine or at a time immediately after starting an engine (e.g., a gasoline engine, a diesel engine), an amount of heat generated from the engine is too small to heat cooling water sufficiently. Therefore, in this case, a combustor is used as a supplementary heating source in a conventional heating apparatus. Further, for reducing nitrogen oxide contained in exhaust gas of the engine, exhaust gas from the engine is recycled to an intake side of the engine so that temperature of a combustion chamber is reduced. Because nitrogen oxide is restricted by reducing the temperature of the combustion chamber, the temperature of the combustion chamber is set as low as possible. However, when a heat exchanger for cooling the exhaust gas of the engine is provided, a space for mounting the heat exchanger in an engine room is necessary, and product cost of the vehicle is increased. On the other hand, in the conventional heating apparatus, heat generated from the engine is not effectively used, and fuel consumption effect of the heating apparatus is decreased. In the heating apparatus, when an exhaust pipe of the engine is simply connected to an exhaust side of the combustor, exhaust gas of the engine may reversely flow into the combustor and the combustor cannot be stably burned because pressure of exhaust gas of the engine is larger than that of the combustor. Further, when exhaust gas of the combustor is directly discharged into the atmosphere, unburned gas contained in the exhaust gas of the combustor may be discharged to the atmosphere.